From Bulbapedia, the community-driven Pokémon encyclopedia.
Maron (Japanese: マサ Masa) is a recurring character in the Pokémon anime. He is the battle judge of the Battle Tower.
He first appeared in Talking a Good Game! where Ash and his friends arrived in the Battle Tower. After Ash told him that he wished to challenged the Frontier Brain, Maron took the group inside and introduced them to the Frontier Brain which was none other than Anabel. The battle between Ash and Anabel began and Maron refereed the battle. After Ash lost, Maron declared Anabel the winner.
He reappeared in Second Time's the Charm where he refereed the rematch between Ash and Anabel, with Ash as the victor this time.